Screw



May 9, 1933. .1. P. THOMPSON SCREW A Filed May 20, 1932 Patented May 9, 1533 JOHN P. THOMPSON, OF PORTLAND, OREGGN/ASSIGNUR, BY DIRECT AND MESNE ASSIGNMENTS, TO H. F. FHILLEPS, F PORTLAND, OEEGGN SCREW Application filed May 20, 1932. Serial No. 612,555.

This invention relates to screws and has stronge' near the outer edge than hitherto for an, object to provide a screw having a possible, a smaller opening need be made in novel screw driving tool receiving aperture the screw, and the product has a neater apwhich permits a single screw driving tool to pearance.

drive screws of various sizes. In the accompanying drawing forming A further object is to provide a screw prop rt of this specification,

vided with a punched aperture having side Figure 1 is a side elevation, partly in secwalls which converge downwardly to a point ion, of a screw constructed in accordance on the axis of the screw and converge radially with the invention.

outward to a knife edge which latter makes lgure 2 is a plan view of the screw.

available the use of automatic machinery to Figure is a plan view of the screw showproduce screws in quantities at reasonable g 11 l l lal axial tapered opening formed 1; therein, and,

With the above and other objects in view Figure 4': is a detail section showing the use the invention consists in certain novel details Of a r lio to enter the tapered opening to of construction and combinations of parts P e t e novel aperture. hereinafter fully described and claimed it fe ing n w to the drawing in which being understood that various modifications like characters of reference designate similar may be resorted to within the scope of the P r s in the Various views, 10 designates a 2G appended claims without departing from the W d crew, although it is to be understood spirit or sacrificing any of the advantages of that the invention is applicable to machine the invention. screws, bolts, and other similar connectors. Hitherto the manufacture of screws with a In prac icing the invention an axial tapered cruciform or other shape of aperture has opening 11 maybe drilled, punched, or otherbeen impractical, several proposed types rewise formed in the head 12 of the screw, as quiring casting, which is so expensive as shown in Figures 3 and 4:. The opening tato make manufacturing costs prohibitive. pers from its outer end downwardly to a point Other types require broaching. This operaon the axis of the screw, and is preferably of tion pushes the metal ahead of the tool and h epth s to eXtend into the shank of the so disturbs the distribution of metal as to groove to the thread thereof, as shown in render the screw head extremely fragile. Figure 1. However, the opening may be of Ordinary screws are cut, rolled or stamped less depth, if desired, although in practice, by automatic machinery and cost but a few about one-third the length of the screw, more cents per hundred to make. It is, therefore, or less, will be found to be practical.

one of the aims of the present invention to Subsequently the tapered opening 11 is enpermit the use of automatic machinery by so larged at the outer end by means of a winged altering the hitherto-proposed cruciform or or star die 14:, for instance, as best shown in other shaped aperture as to retain their de- Figure 4. Preferably the die has four radial sirable virtues, while permitting of the usual wings 15, each of which is tapered downautomatic machinery to "be used with but wardly from the top of the wing to the botslight alterations as to increase the cost of tom thereof, that is, is wedge shaped longimanufacture only to an inznopreciable exten tudinally. Each wing is, in addition, tapered This is accomplished in the main by the novel radially outward. from the axis of the die, radially outward converging walls of the that is, is wedge shaped transversely to proapertures permitting of the use of a star die vide cutting edges all of which converge or similar cutting tool, the wings of which downwardly at like angles toa common pentaper from top to bottom and also taper from etrating point on the axis of the die. Inserthe axis of the die radially outward to knife tion ofthis die into the outer end of the taedges. This novel radially outward taper of pered opening 11 forms a winged incision or the groove'also results in certain additional screw-driving tool receiving aperture 16 in the screw having the exact shape of the die, as shown in Figures 1 and 2.

If desired the initialformation of the tapered opening 11 may be dispensed with and the winged aperture 16 may be formed by use of the die alone. p

Each wing of the aperture 16 in the screw exhibits tapers in. both directions, that is, 1011-.

gitudinally from top to bottom and trans- "versely or radially outward to a knife edge.

More specifically the side walls of each wing converge downwardly in the direction of their length to a point on the axis of the screw and converge radially in the direction oftheir widthto a knife edge. In the preferred embodiment the knife edges of all the wings converge at like angles to a commonpoint on the axis of the screw. The cutting 'of'this novel incision or aperture, as above described, does not weaken the screw to any appreciable extent since, as will be seen by referring to Fig 'ure 1, an adequatewall 17 of metal remains beyond the aperture to the edge of the head, while by referring to Figure 2', it will be seen that large sector-shapedareas 18 exist between the branches or wings of the aperture and the outer edge of the head. As a result the metal is displaced but slightly in counter distinction to the great mass of metal distort-- ed by broaching apertures having square outer ends as has hitherto been proposed.

The winged'aperture 16, above described may be produced by the usual automatic machinery slightly altered to initially form the tapered opening 11 and subsequently'enlarge the outer end of the opening. Alteration may simply'be made to form. the aperture by a single thrust of a cutter such as a winged die. This piercing operation can be accom plished with great rapidity in practice.

. An advantage of the novel aperture will be apparent in that a single screw driving tool, having the general shape of the die 14, may be used to drive screws of various sizes since all apertures will have substantially identical taper from the top of the screw head to'the'bottom point on the axis of the screw. Large screws will simply have deep tapered incisions or apertures while small screws will have apertures of less depth. Also the same die will fit nearly all sizes of screws, in some sizes it will go in for quitea distance, while in other sizes it will advance but a short distance. The same is true of the screw driving tool. 7

From the above description it is thought v that the construction and operation of the in vention will be fully understood without further'explanati'on. 1

. What isclaimed is: V v 1. screw provided with a screw driving 7 toolreceiving wingedaperture, the side walls ofeach wing converging radially in the direction of theirwidth to an edge and converg-f wing converging radially in the direction of their widthto knife edges and converging downwardly in the direction of their length to a common point on the axis of the screw.

4. A screw having a punched screw driving tool receiving winged aperture having side faces converging in the direction of their width radially to knife edges and converging in the directionof their length to a point on the axis of the screw.

In testimony whereof I aiiix my signature.

JOHN P. THOMPSON. V 

